According to an analysis by Cartine, a married couple in New York with $600,000 in wages, $100,000 in qualified dividends and $300,000 in long-term capital gains -- as well as $145,000 in itemized deductions for real estate taxes, mortgage interest and state and local taxes -- would pay about 17 percent, or $37,000, more in U.S. taxes this year.

$450,000 Threshold

By comparison, a family with $600,000 in wages, no investment income and $105,000 in itemized deductions would see about a 2 percent, or $3,000 increase, he said.

Congress set the top tax rate for income above $450,000 for married couples or $400,000 for individuals, after deductions. Those are the same thresholds for the top levy on long-term capital gains and dividends.

Additionally, two new taxes to help finance the 2010 health-care law -- a 3.8 percent surtax on investment income and 0.9 percent added levy on wages -- apply to income of more than $250,000 a year for married couples and $200,000 for individuals.

Lawmakers also reinstated phaseouts of personal exemptions and itemized deductions for adjusted gross income exceeding $250,000 for individuals and $300,000 for married couples.

‘Big Surprise’

“It’s going to be a big surprise when they find out they aren’t going to be able to take all of their itemized deductions,” said Tracy Green, a vice president in tax and financial planning in the advisory unit of Wells Fargo & Co.

With less than two months left in the tax year, advisers and accountants are focusing on clients with closely held business stakes, mutual-fund holdings, charitable donations and retirement accounts to help maneuver around higher rates.

To minimize the effect of the 3.8 percent tax, high earners are reviewing their interests in S corporations and other flow- through entities to see if they can become active rather than passive participants, said William Zatorski, a partner in PricewaterhouseCoopers LLP’s private company services practice. Business income from active participation isn’t subject to the surtax and that shift in S corporations doesn’t trigger self- employment tax, he said.